HiI'm looking at running a Raid 0 setup to run FS9. I have 2 x 120Gb S-ATA drives and 1 x 40Gb IDE for backup. Can anyone advise what cluster size to use and also if there are any true gains using a Raid configeration.

I had to WD 36,7 Raptors in RAID 0 before. 32 kb cluster size. No gain at all I know has one WD 74 GB Raid which is quiter and faster. Yes faster in just about everything in some programmes the RAID managed to give almost equal performance at the expense of more CPU utilization.I think anandtech had an eyeopening article of RAID if I am not misstaken. It do better in synthetic tests than real world application.Now the 36,7 GB Raptor is slower than the 74 GB Raptor to start with but not that much that would explain the why they not even in RAID manage to keep up with the faster Raptor. One explanation may be that access times go up when running raid.